I have two computers in the same room. My main computer only gets about 2-3 mbps while on a Cat6 cable. My back up pc gets over 900 mbps while on the same Cat6 cable. The backup has also been tested with a Wi-Fi card and it gets well over 100 mbps. I have tried several options from replacing the cables, moving locations, switching to Wi-Fi and even resetting the modem/router.

There are two other PCs in the house running on the same Internet and with cat6 cables as well. only one of the other 2 has encountered a similar issue with internet speed. The one having issues belongs to my sibling. So the only 2 computers in the house that have internet speed issues are used primarily for gaming.

Is there a program that can be causing a cap on the internet flow into said gaming computers?